820 transaxles. I dont even have one myself lolAnyways, to generally find any 800 series transaxle, look for older murrays sears and craftsman mowers. The number plate (or a tag as you would call it) is found somewheres near the brake caliper. (Normally under the the brake caliper, but it can be beside it) Ive had pretty good luck with murrays as ive gotten a 5 speed 801 (i have been told they have the same gears as an 820, and it has a great diff/axle setup) from a murray. Also got an 814 from a guy who only had older craftsman tractors, but i dont know where he got it so i can't pin a mower to that transaxle. But anyways, good luck on your search!